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Oxidation and microstructure of SiCf/SiC composites in moist air up to 1600°C by X-ray tomographic characterization |
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| Authors: | Zilong Lu Bixiong Bie Aimin Pang Wei Li Jianling Yue Xiaozhong Huang Haitang Yang |
| Affiliation: | 1. School of Materials Science and Engineering, Central South University, Changsha, Hunan, China
Hunan Province Key Laboratory of New Specialty Fibers and Composite Material, Central South University, Changsha, Hunan, China;2. Key Laboratory of Advanced Technologies of Materials, Ministry of Education, Southwest Jiaotong University, Chengdu, Sichuan, PR China;3. Science and Technology on Aerospace Chemical Power Laboratory, Hubei Institute of Aerospace Chemotechnology, Xiangyang, Hubei, PR China;4. Hunan Province Key Laboratory of New Specialty Fibers and Composite Material, Central South University, Changsha, Hunan, China;5. Hunan Province Key Laboratory of New Specialty Fibers and Composite Material, Central South University, Changsha, Hunan, China State Key Laboratory of High Performance Complex Manufacturing, Central South University, Changsha, Hunan, China |
| Abstract: | SiCf/SiC composites that possess PyC or BN interface layers were fabricated and then oxidized in moist air at 1000, 1200, 1400, and 1600°C. High-resolution CT was used for capturing 3D images and quantifying the SiC phase, mesophase, and voids. The oxidation behavior and microstructural evolution of SiCf/SiC with PyC or BN interface are discussed in this study. The microstructure of the SiCf/SiC with a PyC layer was seriously damaged in moist air at high temperature, whereas the BN interface layer enhanced the oxidation resistance of the SiCf/SiC. These results are also confirmed by using XRD, oxidation mass gain, tensile testing, and SEM measurements. The results of the oxidation behavior and microstructural evolution for SiCf/SiC oxidized in dry air are also compared with the results of this study. Comparing the SiCf/SiC with a PyC interface layer, the composite with a BN interface layer oxidized in moist air exhibits a high void growth rate and a low SiO2 grain growth rate from 1000 to 1600°C. This work will provide guidance for predicting the service life of SiCf/SiC for multiscale damage rate models of materials at a local scale and will also provide guidance on the life service design of SiCf/SiC materials. |
| Keywords: | boron nitride ceramic matrix composites interfaces microstructure Tomography X-ray computed |